With the above-described impeller, the inner circumferential-side blade portion of the impeller blade is arranged so as to be located on the inner circumferential side of the substrate and oriented so as to extend in the direction along the rotary shaft core and have a tip side that is bent, thus enabling a fluid to be efficiently drawn from the inner circumferential side of the substrate by the inner circumferential-side blade portion.
When the above-described conventional impeller is produced, the impeller blade is divided into the inner circumferential-side blade portion and the outer circumferential-side blade portion, which are created separately, and then the inner circumferential-side blade portion and the outer circumferential-side blade portion are assembled so as to be integrated.
The inner circumferential-side blade portion is provided so as to be integrated with the substrate of an inducer that is attached to the inlet side of the impeller, for example (e.g., see Patent Document 1).